1. Field of the Invention
The present invention relates to a system of retrieving and analysing biological samples that improves the accuracy and reproducibility of results obtained from analysis of mucoid and/or suspension samples. The present invention provides means of promoting standardization of sample collection and analysis between clinical studies and between clinical centres. More particularly, this invention relates to a two vial interconnected filtration system, that allows samples to pass from a sample tube to a filtrate tube, through standardized filters and to be treated with standardized reagents for analysis.
2. Description of the Prior Art
Collection and analysis of biological samples have been valuable for correct diagnosis and therapy of a wide variety of different conditions. In particular, airway inflammation, which is present in many diseases including asthma, chronic obstructive pulmonary disease and lower respiratory tract infections, may be detected from analysis of sputum. Sputum is defined as the expectorated lower respiratory secretions and is composed of fluid and cellular components including eosinophils, neutrophils, lymphocytes, macrophages, and epithelial cells. Analysis of the cells present in sputum is the best, presently known way to characterise the severity and type of inflammation present. This information in conjunction with other clinical parameters may be used to determine specific courses of treatment. Increases in certain types of cells may indicate an infection or an inflammation that would be more sensitive to one course of treatment as opposed to another. Hence, it is important that the collection, processing and analysis of sputum, aspirate, or other biological fluids, are as accurate as possible.
Presently, methodology used for collecting, processing, filtering and analysing biological samples, such as sputum, vary from lab to lab. Variations in technique will cause variations in the results obtained during analysis such as, detection of numbers of cells and fluid phase indices. This becomes important in relation to reproducibility, validity, responsiveness and comparison of results within and between samples. If the results cannot be compared between tests, or if the results of a test cannot be reproduced, valid diagnosis and accurate courses of treatment cannot be determined. Procedures and the equipment used must therefore be standardised.
An important part of the process for analysis of certain biological samples, is the filtration of the collected sample and the collection of the filtrate containing the single cell or cellular suspension that the technician wishes to analyse. Variation in the protocol for processing samples for analysis is currently one area that causes variation in results between tests and between testing centres. The variation in results is largely due to of the wide variability in protocols, reagents, and materials currently used for the collection and analysis of samples.
When dealing with limited quantities of samples for analysis, even a minute loss of sample could drastically alter the results of a test. The size, number and type of cells found in the filtrate vary depending on the size and type of filter used. Incorrect filter pore size may result in selective cell loss and incorrect cell differentials. Incorrect filter mesh type and size may result in cell loss due to absorption of small samples. Improper placement of the filter may allow the filtrate to become contaminated by debris. Contaminates or debris may cause problems in analysis by varying the results that are produced, or by clogging apertures of automated cell counters. In addition to this, each time that a sample is handled and transferred from one vessel to another there will be loss of sample volume and content causing errors in the analysis and the final results of the experiment. Selection of the filter type and size necessary for removal of undesirable contaminants and debris is an important component that contributes to reproducible and valid results.
There is a need for a system that will standardize the protocol used by various technicians and labs so that results may be cross-referenced and prepared for diagnostic purposes between samples, between tests and between laboratories. Reasons for comparing test results between samples would be, for example, if a patient is being treated by a certain type of drug it is desirable to know if the prescribed drug is having an effect on the condition present.
Samples may be collected at various points during a course of treatment and comparison of measurements such as cell counts and/or fluid phase indices may be analysed to determine effect of treatment. Clinical treatment may then be adjusted accordingly. Lack of standardized tests complicate comparison of analysis results of different samples, which may make it impossible to make an absolute clinical diagnostic decision, and to monitor treatment. It would not be definitive if variations in results were due to erroneous procedures or to actual change as a result of treatment. A system developed with a standardized collection and filtration procedure could eliminate many errors in the handling, examination and measurement of a sample. A system in which a sample could be collected in a sample holder, transported to the lab and then filtered through an internal filtration conduit into a second receiving vial, would be a desirable contribution to science. Currently, in most cases, samples are being collected in one collection vessel or sample holder. The sample is then transported to a lab. The sample is then poured from this vessel onto filters of varying sizes depending on the protocol in use. The filtered sample, or filtrate, is then received in a second receiving vessel, or filtrate holder. Transfers of a sample from vessel to vessel many times will cause loss of volume and cell yield.
In accordance with the invention disclosed herein, it will be seen that a device is used for collecting a sample, filtering the sample through a filter with a standardized mesh size, and receiving the filtered sample directly into another connected vessel. A device capable of performing these steps in a closed system will provide a solution to many of the aforementioned problems. The steps of collection, filtration, collection of filtrate and analysis, could be conducted within one system and would eliminate transfer of sample. This may reduce chances of sample volume being lost, wrong filter sizes or types being used or improper filter positioning, thus preventing debris from passing through into the filtrate causing contamination. This system will use a standardized filter type and pore size, or have various filters available within a kit for specific purposes. The collected samples could be treated with reagents, in the collection vial or sample holder if desired. Treating the sample in the collection vial may therefore eliminates transfer steps and reduces sample loss. Use of a standardised system having standard filters, reagents, and apparatuses, would therefore allow all technicians to use the same protocol and result in comparable data and thus be reproducible and valid.
Furthermore, a system that eliminates or greatly reduces human exposure to the sample is greatly desirable in settings where that sample may contain contagions. In accordance with the present invention, the collection or sample holder may be sealed from human contact from the point of collection. Both the receiving or collection vials may have reagents placed in it prior to collection or processing.
A device that could reduce the number of errors in processing a sample, increase the validity, reproducibility and simplify a process would be of great interest to pharmaceutical companies, hospitals, and research laboratories. There could be a decrease in the number of man-hours necessary and a reduction in the amount of reagents and equipment used for analysis, therefore a reduction in costs.
Availability of a standard filtering system along with various standardized filters, and testing reagents in a kit would provide a standardized protocol and be an advantage for producing valid and reproducible result
The foregoing and other objects and advantages of the present invention will become more apparent from the following summary and the detailed description of the present invention, when taken in conjunction with the accompanying drawings, the scope of which will be pointed out in the appended claims.